Drives for control enclosures
Storwize® V3500 enclosures use different drives, depending on the generation of your control enclosure model. An enclosure can hold up to 12 3.5 in. (8.89 cm) drives or up to 24 2.5 in. (6.35 cm) drives.
The drives are in the front of the enclosure. The 12 large form factor (LFF) 3.5 in. (8.89 cm) drives are mounted horizontally in four columns with three rows. The 24 small form factor (SFF) 2.5 in. (6.35 cm) drives are mounted vertically in one row.
Important: Drive slots cannot be empty. Install a drive assembly or blank carrier in
each slot.
Note: Drives that are sold as Storwize V3500 options are the only drives that are supported. For more information, see the Support website.
Figure 1
shows a large form factor 3.5 in. (8.89 cm) drive with the latching mechanism open.
Figure 1.
Large form
factor horizontal drive 

Figure 2
shows a small form factor 2.5 in. (6.35 cm) drive with the latching mechanism open.
Figure 2. Small form
factor vertical drive 
